At least two people were killed and dozens injured in clashes between Shiites and Sunnis last night in Beirut and other Lebanese cities, according to security officials and official media reports.

A man was killed north of Sidon and another person died in fighting in Tripoli, officials said. At least six people were injured in Beirut and ten in Tripoli. A reporter for the Associated Press has seen Monday dozens of armed men roam the streets of the predominantly Sunni Tarik Jdideh district in Beirut. They set up checkpoints, stopping cars and asking people for their destination and origin.

A local resident reported that exchanges of fire began shortly after midnight and lasted until sunrise. "We could not sleep because of the gunfire. There were also explosions," she said.

In Tripoli, residents saw dozens of soldiers deployed around the city to try to restore calm. The military also set up checkpoints, searching cars and asking to verify identity.

Many Lebanese Sunnis support the Syrian opposition to Bashar al-Assad, while Shiites tend to support Assad. The tension is high in Lebanon after the bombing that killed Friday the Sunni General Wissam al-Hassan, head of the Lebanese intelligence.

The fear that the conflict in Syria will spread into Lebanon is great, and the death of the intelligence chief put question marks on the fragile political balance of the country. Many figuers have accused Syria of standing behind the assassination of General al-Hassan and protesters have attacked the government headquarters on Sunday, before being pushed back by the army.